Dosage and total Energy from radioactive medicine.

[NickMcCartney]

I can't seem to get this started in the right direction. Any help is appreciated.

As part of a treatment program, a patient ingests a radioactive pharmaceutical containing P32,15, which emits beta rays with an of 1.50. The half-life of is 14.28 , and the initial activity of the medication is 1.34 .

Part A
How many electrons are emitted over the period of 7.00 days?

Part B
If the rays have an energy of 705 keV , what is the total amount of energy absorbed by the patient's body in 7.00 ?

Part C
Find the absorbed dosage in rem, assuming the radiation is absorbed by 110 grams of tissue.

 

[NickMcCartney]

Here is what I have done so far.

Part A.

Converted half life (T 1/2) into seconds. = 1.234e6 s
Found the decay constant (lambda) = ln(2)/1.234e6 = 5.617e-7
Found N0 (nuclei present at t=0) = R0/lamda = 2.386e12
Found N= A-Z = 32-15=17

Tried to plug into equation: N=N0e^(-(lambda)(t)) where I put the 7 days (in seconds) into t which came out to 1.7e12, which was wrong. I don't know where to go from here.